************************************************************************** Security Bulletin 9538 DISA Defense Communications System September 29, 1995 Published by: DISN Security Coordination Center (SCC@NIC.DDN.MIL) 1-(800) 365-3642 DEFENSE INFORMATION SYSTEM NETWORK SECURITY BULLETIN The DISN SECURITY BULLETIN is distributed by the DISN SCC (Security Coordination Center) under DISA contract as a means of communicating information on network and host security exposures, fixes, and concerns to security and management personnel at DISN facilities. Back issues may be obtained via FTP (or Kermit) from NIC.DDN.MIL [192.112.36.5] using login="anonymous" and password="guest". The bulletin pathname is scc/disn-security-yynn (where "yy" is the year the bulletin is issued and "nn" is a bulletin number, e.g. scc/disn-security-9531). ************************************************************************** + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + ! ! ! The following important advisory was issued by the Automated ! ! Systems Security Incident Support Team (ASSIST) and is being ! ! relayed unedited via the Defense Information Systems Agency's ! ! Security Coordination Center distribution system as a means ! ! of providing DISN subscribers with useful security information. ! ! ! + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + -----BEGIN PGP SIGNED MESSAGE----- <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Automated Systems Security Incident Support Team _____ ___ ___ _____ ___ _____ | / /\ / \ / \ | / \ | | / Integritas / \ \___ \___ | \___ | | < et /____\ \ \ | \ | | \ Celeritas / \ \___/ \___/ __|__ \___/ | |_____\ <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bulletin 95-36 Release date: Sept. 28, 1995, 8:45 PM EDT (GMT -4) SUBJECT: SunOS 4.1.x sendmail "-oR" option vulnerability. SUMMARY: A vulnerability exists in the SunOS 4.1.x sendmail program that allows local users to gain root privileges. Other versions of sendmail are not vulnerable to this problem. An exploit for the sendmail "-oR" option vulnerability has been made available in various public forums. ASSIST recommends immediate action be taken to correct this problem on all affected DoD systems. BACKGROUND: A vulnerability exists in the way the SunOS 4.1.x version of sendmail processes the "-oR" option. The problem may be exploited by local users to gain root access. This vulnerability has been verified to exist for SunOS 4.1.x (sendmail SunOS patch levels up to and including 100377-19, 101665-04, and 102423-01). In the current absence of suitable patches, sites may either apply a workaround solution or upgrade their sendmail to Eric Allman's 8.6.12 sendmail program which contains no known vulnerabilities. Note that converting from SunOS sendmail to Version 8.6.12 sendmail may require significant effort. See RECOMMENDED SOLUTIONS below for info on the workaround and Eric Allman's sendmail 8.6.12. IMPACT: Users with accounts on the system may exploit the problem and gain root access. RECOMMENDED SOLUTIONS: Sun Microsystems is in the process of developing and testing patches that address several recent reported sendmail vulnerabilities. In the interim, ASSIST recommends implementing the workaround specified below in (A), or installation of Eric Allman's 8.6.12 sendmail as described in (B) below. A. SunOS 4.1.x sendmail "-oR" option vulnerability workaround. - -------------------------------------------------------------- For sites that wish to continue using their existing SunOS version of sendmail, the sendmail wrapper can be used as an interim solution until a SunOS patch is issued. This wrapper is available by anonymous FTP from: assist.mil:/pub/tools/unix/sendmail/sendmail_wrapper.c MD5 = f4049cc56075ddb142f5bd70a53ba341 This wrapper will provide protection against the "oR" and some older vulnerabilities as well. Please note that this wrapper does not address all known vulnerabilities and should be considered as a temporary workaround to this problem. This wrapper will log (syslog) possible attacks to facility LOG_MAIL with severity LOG_ERR. Sites may wish to customize these values in the sendmail wrapper or their syslog.conf files to suit their requirements. B. Replacing SunOS sendmail with Eric Allman's Version 8.6.12. - -------------------------------------------------------------- Replace the SunOS sendmail with Eric Allman's Version 8.6.12 sendmail. This may require significant effort to complete. Version 8.6.12 sendmail contains no known security vulnerabilities. Sendmail version 8.6.12 can be obtained from: ftp.cs.berkeley.edu:/ucb/sendmail/ sendmail.8.6.12.* Information to assist sites in converting from Sun's sendmail to Version 8 can be found in the sendmail.8.6.12.misc.tar.Z file which is in the directory above and the assist.mil directory referenced in (A). The existing SunOS sendmail binaries (sendmail and sendmail.mx) should be disabled by setting the permissions to mode 0700. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ASSIST would like to thank the AUSCERT for information contained in this bulletin and the sendmail_wrapper.c program. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ASSIST is an element of the Defense Information Systems Agency (DISA), Center for Information Systems Security (CISS), that provides service to the entire DoD community. Constituents of the DoD with questions about ASSIST or computer security issues, can contact ASSIST using one of the methods listed below. Non-DoD organizations/ institutions, contact the Forum of Incident Response and Security Teams (FIRST) representative. To obtain a list of FIRST member organizations and their constituencies send an email to docserver@first.org with an empty "subject" line and a message body containing the line "send first-contacts". ASSIST Information Resources: To be included in the distribution list for the ASSIST bulletins, send your Milnet (Internet) e-mail address to assist-request@assist.mil. Back issues of ASSIST bulletins, and other security related information, are available from the ASSIST BBS at 703-607-4710, 327-4710, and through anonymous FTP from assist.mil (IP address 199.211.123.11). Note: assist.mil will only accept anonymous FTP connections from Milnet addresses that are registered with the NIC or DNS. If your system is not registered, you must provide your MILNET IP address to ASSIST before access can be provided. ASSIST Contact Information: PHONE: 800-357-4231, COMM 703-607-4700, DSN 327-4700. ELECTRONIC MAIL: assist@assist.mil. ASSIST BBS: COMM 703-607-4710, DSN 327-4710, leave a message for the "sysop". FAX: COMM 703-607-4735, DSN 607-4735 ASSIST uses Pretty Good Privacy (PGP) 2.6.2 as the digital signature mechanism for bulletins. PGP 2.6.2 incorporates the RSAREF(tm) Cryptographic Toolkit under license from RSA Data Security, Inc. A copy of that license is available via anonymous FTP from net-dist.mit.edu (IP 18.72.0.3) in the file /pub/PGP/rsalicen.txt, and through the world wide web from http://net-dist.mit.edu/pgp.html. In accordance with the terms of that license, PGP 2.6.2 may be used for non-commercial purposes only. Instructions for downloading the PGP 2.6.2 software can also be obtained from net-dist.mit.edu in the pub/PGP/README file. PGP 2.6.2 and RSAREF may be subject to the export control laws of the United States of America as implemented by the United States Department of State Office of Defense Trade Controls. The PGP signature information will be attached to the end of ASSIST bulletins. Reference herein to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by ASSIST. The views and opinions of authors expressed herein shall not be used for advertising or product endorsement purposes. - -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.6 mQCNAi4uZ40AAAEEAM1uraimCNeh5PtzX7KoGxC2u8uMTdl8V5sujk3MHbWvCuOM W0FqDy5s9iwfQLZWzJ7cbM6L0mNOj8eJGoz7TqGKZDDRFlKAwg0x8joleZLC2gXw FVdF/g6Mdv7ok7heoa+Y//YMeADnsSrmzqLCnhFbKYffww3EbdH6sbnW3Io9AAUR tB9BU1NJU1QgVGVhbSA8YXNzaXN0QGFzc2lzdC5taWw+iQCVAwUQL1xx7tH6sbnW 3Io9AQEBYwP9FvIJbnKjtMLUj8ghd6hophSx8WZnfQsOmZX/BbX8vKz1a5BkBn4q ANvW+uKGdUlE8LLMEm1PD59Cihcb3OoWDOU8zIOIErvry4eqa+LzEXV8nnBdes+A a1MCMGSz+K3OaP78lQ7JCGoY9TXTWIelfAdBVBG4VQcSQRn8tjRdG2e0KEFTU0lT VCBUZWFtIDxhc3Npc3RAYXNzaXN0Lmltcy5kaXNhLm1pbD6JAJUCBRAuLnHoh0Y9 0jC+b6kBAU0TA/4yXSL7K6tcfVm9ACnP4crCoutFM2w10e7YKxD850ajhWrh6rI9 O+sjU5WObqiPJ7sZHdEw/KARzPSijH/5h8HlyYa6ClksWxYuymzCsUYYJctdjcGr uakfXgYQ1TkkyUfNrN5G90NuRK/vTRe7bkmyGNYjN9Njac1Q18WVF59Chg== =d5rP - -----END PGP PUBLIC KEY BLOCK----- -----BEGIN PGP SIGNATURE----- Version: 2.6 iQCVAwUBMGtBDNH6sbnW3Io9AQGaAwQAo72GvVJELMDsSTUiuvZqdXol1grmwvv0 Uy0qNEwbaG+nkV9yknQKN1fHh68VwfZHdH78wNEamKPfcfNGFEVatVS51bgX13WD 494lgJienQnBhOel13hO4cNSTcYUZq/vowDoP9VVT1pXMA5judeBtjJhi162ivIc Xma+nkfbpIs= =s3GE -----END PGP SIGNATURE----- **************************************************************************** * * * The point of contact for NIPRNET security-related incidents is the * * Security Coordination Center (SCC). * * * * E-mail address: SCC@NIC.DDN.MIL * * * * Telephone: 1-(800)-365-3642 * * * * NIC Help Desk personnel are available from 7:00 a.m.-7:00 p.m. EST, * * Monday through Friday except on federal holidays. * * * **************************************************************************** PLEASE NOTE: Some users outside of the DOD computing communities may receive DISN Security Bulletins. If you are not part of the DOD community, please contact your agency's incident response team to report incidents. Your agency's team will coordinate with DOD. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained by sending email to docserver@first.org with an empty subject line and a message body containing the line: send first-contacts. This document was prepared as an service to the DOD community. Neither the United States Government nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government. The opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes.